Hi all, This is the third revision of an RFC for adding to xfsprogs support for tracking reverse-mappings of physical blocks to file and metadata; and support for mapping multiple file logical blocks to the same physical block, more commonly known as reflinking. Given the significant amount of re-engineering required to make the initial rmap implementation compatible with reflink, I decided to publish both features as an integrated patchset off of upstream. This means that rmap and reflink are now compatible with each other. The patch set is based on the current (4.2.0+) for-next branch. This code should be relatively bug-free, and the bulk of the patches are to teach xfs_repair how to record all mappings and to use that data both to regenerate the reference count data (refcntbt) and the reverse mapping index (rmapbt). There are way too many patches to discuss them individually, but roughly speaking they're grouped by functional area: 0. Cleanups 1. Implement reflink and dedupe in xfs_io 2. Spot-check and fuzz v5 filesystems in xfs_db (otherwise the test/scratch fs checks in xfstests get unhappy) 3. rmapbt support 4. rmapbt rebuilding in xfs_repair 5. refcntbt support 6. refcntbt rebuilding in xfs_repair Issues: * I'm not 100% sure xfs_repair correctly handles rebuilding all the XFS_RMAP_OWN_AG rmap entries (which are the bnobt, cntbt, rmapbt, and the AGFL). * General shakiness of the code that spots errors in the rmapbt and refcntbt. Given that we're either readonly or rebuilding them anyway, I wonder if it matters... * Under certain circumstances, mkfs underestimates the minimum log size and the kernel refuses to mount. The last patch in the set hacks around this in an ugly way. If you're going to start using this mess, you probably ought to just pull from my github trees for kernel[1], xfsprogs[2], and xfstests[3]. This is an extraordinary way to eat your data. Enjoy! Comments and questions are, as always, welcome. --D [1] https://github.com/djwong/linux-xfs-dev/commits/master [2] https://github.com/djwong/xfsprogs/commits/for-next [3] https://github.com/djwong/xfstests/commits/master _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
